The modern forestry industry is continually seeking to improve efficiency in processing wood. It is well-known to mount a timber-working head, for example in the form of a harvesting head, to a forestry work machine to perform a number of functions in connection with timber. Such heads may be used to grapple and fell a standing tree and process the felled tree by delimbing, possibly debarking (depending on the configuration of the head), and cutting the stem of the tree.
Many such harvester heads have the ability to measure the diameter and length of a log and automatically determine the optimal position of saw cuts in order to maximise the value of that log.
U.S. Patent Application Publication No. 2004/0074563 illustrates a method of producing a log cutting solution based on a model of a delimbed log. The disclosure refers to optimising the cutting based on either prioritising particular lengths, or the total dollar value of the combination of lengths which may be produced from a log.
Automation of this process would be expected to improve productivity. Previously, an operator may have been required to calculate optimal value manually, or manually control the harvester head to perform cutting at previously measured and marked points along the stem. U.S. Pat. No. 5,457,635 describes a portable apparatus for measuring and marking a felled tree prior to it being processed. This either requires additional labour units to complete, or takes harvester operators away from their core tasks, resulting in low productivity.
However, there are instances which still require the operator to manually determine and perform optimisation. In particular, systems such as U.S. Patent Application Publication No. 2004/0074563 do not account for situations where the log includes a defect such as a broken top which will significantly affect the value of the wood at that point.
A stem optimisation system which seeks to account for defects in a tree stem is provided by the ForestBucker™ manufactured by Electronics123 Limited at the time of filing the present application, see <http://forestbucker.electronics123.co.nz/Home/ForestBucker>. This system scans a tree stem in order to identify defects in the stem and develops a cutting solution which accounts for these defects as well as length and profile.
However, this system requires the use of large scale equipment, such as a trolley configured to run on tracks the length of the log. This set up requires a significant amount of space and a relatively even terrain, which may not be available at the site in which the harvester is operating. Further, one of the advantages to modern mechanical harvester heads is the ease with which they may be fitted to wheeled or tracked vehicles in order to improve portability and enable them to be used in relatively rough terrain. The use of a log scanner at a fixed location would limit the usefulness of such harvester heads.
Additionally, a separate scanning or measurement apparatus would require additional processing steps—including the placement of the log for scanning, waiting for the scanning to be completed, and subsequently retrieving the log in order to perform the sawing. The associated downtime for the harvester head and harvester operator would reduce productivity.
As such, where a significant defect is identified by an operator during processing of a log, the operator is currently required to manually determine the optimal cutting solution for the log. This process takes time and causes operator stress and fatigue, which may in turn lead to errors in optimisation and lost value to the forest owner.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Further aspects and advantages of the present disclosure will become apparent from the ensuing description which is given by way of example only.